A multiplex assay for the simultaneous detection of antibodies against 15 Plasmodium falciparum and Anopheles gambiae saliva antigens

Abstract

BackgroundAssessment exposure and immunity to malaria is an important step in the fight against the disease. Increased malaria infection in non-immune travellers under anti-malarial chemoprophylaxis, as well as the implementation of malaria elimination programmes in endemic countries, raises new issues that pertain to these processes. Notably, monitoring malaria immunity has become more difficult in individuals showing low antibody (Ab) responses or taking medications against the Plasmodium falciparum blood stages. Commonly available techniques in malaria seroepidemiology have limited sensitivity, both against pre-erythrocytic, as against blood stages of the parasite. Thus, the aim of this study was to develop a sensitive tool to assess the exposure to malaria or to bites from the vector Anopheles gambiae, despite anti-malarial prophylactic treatment.MethodsAb responses to 13 pre-erythrocytic P. falciparum-specific peptides derived from the proteins Lsa1, Lsa3, Glurp, Salsa, Trap, Starp, CSP and Pf11.1, and to 2 peptides specific for the Anopheles gambiae saliva protein gSG6 were tested. In this study, 253 individuals from three Senegalese areas with different transmission intensities and 124 European travellers exposed to malaria during a short period of time were included.ResultsThe multiplex assay was optimized for most but not all of the antigens. It was rapid, reproducible and required a small volume of serum. Proportions of Ab-positive individuals, Ab levels and the mean number of antigens (Ags) recognized by each individual increased significantly with increases in the level of malaria exposure.ConclusionThe multiplex assay developed here provides a useful tool to evaluate immune responses to multiple Ags in large populations, even when only small amounts of serum are available, or Ab titres are low, as in case of travellers. Finally, the relationship of Ab responses with malaria endemicity levels provides a way to monitor exposure in differentially exposed autochthonous individuals from various endemicity areas, as well as in travellers who are not immune, thus indirectly assessing the parasite transmission and malaria risk in the new eradication era.

Serological markers to measure recent changes in malaria at population level in Cambodia

“…Several research groups recently developed multiplex serological assays for the detection of Abs against Plasmodium Ags [27, 38, 45–48]. Previous studies combining short- and long-lived markers for Plasmodium have generated knowledge about past and recent changes in malaria transmission within communities [13, 40, 49].…”

“…In addition, two peptides specific for the Anopheles gambiae saliva protein gSG6 (salivary gland 6) were included. All peptides were chemically synthesized with an added N-terminal cysteine residue and BSA (bovine serum albumin, Sigma-Aldrich, St. Louis, USA) [27] by GeneCust Europe (Dudelange, Luxembourg). The recombinant proteins were produced as described in Table 1.…”

Development and evaluation of a multiplex screening assay for Plasmodium falciparum exposure

“…Bead-based multiplex technology such as the xMAP® system allows simultaneous measurement of antibodies against multiple antigens which should theoretically increase sensitivity. Multiplex assays have been developed for immune epidemiological studies in malaria (Fouda et al, 2006;Ambrosino et al, 2010;Fernandez-Becerra et al, 2010) The aim of this study is to develop and determine the potential and accuracy of a multiplex assay (MPA) for screening donor blood for P. falciparum antibodies compared to IFAT.…”

Single-cell technologies for monitoring immune systems

“…Variations of these assays facilitate highly multiplexed or high-throughput analysis: bead arrays (for cytokine detection, such as Luminex technology) and gene microarrays use combinations of spectral and spatial delineation of analytes to measure dozens to thousands of parameters for a given sample. These tools for monitoring the immune system have provided exceptional insights into disease pathogenesis and immunity, including the detection (and discrimination) of respiratory viral pathogens 1 , high-throughput analysis of antibody responses in large studies of malaria and hepatitis B 2 , and multidimensional profiles of vaccine-induced T cells 3 . Nonetheless, these technologies make the analysis of rare subsets of cells (like antigen-specific T cells or B cells) challenging, if not impossible.…”